Sound Examples for Chapter 9: Beat-Based Signal Processing

[S:77] Maple Drums (MapleDrums.mp3 1:51). The beat of the Maple Leaf Rag is regularized so that each beat interval contains the same number of samples. A preprogrammed drum line is superimposed to emphasize the metronomic regularity.


[S:78] Rhythmic Beat Manipulations (MapleBeatMod(a).mp3 1:41), (MapleBeatMod(b).mp3 1:41), (MapleBeatMod(c).mp3 1:41) Individual beats of the Maple Leaf Rag are stretched and compressed and then played together with the original.


[S:79] Polyrhythmic Rags #1 and #2 (PolyrhythmicRag1.mp3 1:36), (PolyrhythmicRag1.mp3 1:36) Individual beats of the Maple Leaf Rag are stretched by a factor of 4/3 and every fourth beat is removed. This is then played simultaneously with the original. See Fig.part(d).

[S:80] Changing Tempo The tempo of the Maple Leaf Rag is changed in a variety of ways using the phase vocoder PV.m. See Sect. 9.1.
  1. Maple Leaf Rag at quarter speed (MapleQuarter.mp3 1:00).
  2. Maple Leaf Rag at half speed (MapleHalf.mp3 1:00).
  3. Maple Leaf Rag at double speed (MapleDouble.mp3 1:00).
  4. Maple Leaf Rag at four times normal tempo (Maple4x.mp3 0:27).
  5. Maple Leaf Rag at eight times normal tempo (Maple8x.mp3 0:14).
  6. Maple Leaf Rag at 16 times normal tempo (Maple16x.mp3 0:07).
  7. Maple Leaf Rag at 32 times normal tempo (Maple32x.mp3 0:03).
  8. Maple Leaf Rag at 64 times normal tempo (Maple64x.mp3 0:01).

[S:81] Maple Sleep Rag (MapleSleepRag.mp3 3:53). An elaboration of the half speed version of the Maple Leaf Rag. See Sect. 9.1.

[S:82] Time Stretching I Extreme time stretching can be an interesting special effect even when not synchronized with the beat. See Sect. 9.1.
  1. Gong (Gong.mp3 0:05). A single strike of a gong.
  2. Long Gong (LongGong.mp3 2:26). The same gong, stretched in a variety of ways to bring out details of the evolution of the sound that are impossible to hear at the normal rate.

[S:83] Time Stretching II Extreme time stretching using beat boundaries. See Sect. 9.1.
  1. Very Slow # 1 (VerySlow1.mp3 4:00). A melange of beats chosen from several different songs, all equalized in time and then stretched by a factor of eight.
  2. Very Slow # 2 (VerySlow2.mp3 4:00). The same as (i), but modified with a variety of beat-based filters.
  3. Very Slow # 3 (VerySlowInspective.mp3 3:55). The piece in (iv) is slowed by a factor of eight.
  4. Inspective Latency (InspectiveLatency.mp3 3:47). An adaptively tuned piece from is presented here for comparison with its time stretched version in (iii).

[S:84] Beat Filtered Rag (BeatFilteredRag.mp3 1:51). A variety of beat-based filters and delay effects are applied to the Maple Leaf Rag. See Sect. 9.2.

[S:85] Beat Gated Rag (BeatGatedRag.mp3 1:51). A variety of beat-based gates and envelopes are applied to the Maple Leaf Rag. See Sect. 9.2.

[S:86] Gar Fael Elpam (GarFaelElpam.mp3 0:44). The first 44 seconds of the Maple Leaf Rag is played backwards. See Sect. 9.3.
[S:87] Beat Reversed Rag (BeatReversedRag.mp3 3:44). The audio in each beat interval is reversed in time so that the sounds are backwards but the piece itself moves forwards. It appears as the Maple Leaf Rag is played on an organ or calliope. See Sect. 9.3.


[S:88] Wrongly Reversed Rag (WronglyReversedRag.mp3 1:44). The audio is reversed in approximately beat-sized chunks, but with boundaries that bear no relationship to the beat boundaries. See Sect. 9.3.


[S:89] Averaged Sublimes (Sublime2.mp3 0:30), (Sublime5.mp3 0:30), (Sublime30.mp3 0:30), (Sublime50.mp3 0:30) In each case, N successive 8-beat cycles (measures) of the "hip hop sublime" are averaged together. See Sect. 9.4.

[S:90] Noisy Leaf Rag (NoisyLeafRag.mp3 1:06). The noise floor is calculated at each beat and all information above the noise floor is removed. When transformed (via the IFFT) back into the time domain, only the noisy parts of the sound remain. See Sect. 9.5.
[S:91] Maple Noise Rag (MapleNoiseRag.mp3 1:52). The Noisy Leaf Rag (the only sound source used in this composition) is augmented with a variety of beat-based techniques such as those of Sect. 9.2. See Sect. 9.5.

[S:92] Just Noise Rag (JustNoiseRag.mp3 1:30). Another elaboration of the Noisy Leaf Rag . See Sect. 9.5.

[S:93] Noisy Souls (NoisySouls.mp3 2:39). Soul (the only sound source used in this composition) is augmented with a variety of beat-based techniques such as those of Sect. 9.2. See Sect. 9.5.

[S:94] Noisy StrangeTree (NoisyStrangetree.mp3 1:01). All information above the noise floor of is removed at each beat. The voice is particularly striking. In the verse, the consonants are (almost) identifiable. In the chorus, where long notes are sustained, the voice effectively disappears. See Sect. 9.5.

[S:95] StrangeTree (StrangeTree.mp3 3:36). An early composition by the author with a straightforward vocal is used to demonstrate many of the signal processing techniques.

[S:96] Signal Leaf Rag (SignalLeafRag.mp3 1:06). All information below the noise floor is removed. When transformed (via the IFFT) back into the time domain, the noisy percussive elements have been removed, leaving the tonal material intact. See Sect. 9.5.

[S:97] Listening to Peaks (Maple1Peaks.mp3 1:06), (Maple3Peaks.mp3 1:06), (Maple15Peaks.mp3 1:06), (Maple50Peaks.mp3 1:06), (Maple250Peaks.mp3 1:06) Peaks are identified within each beat interval in the Maple Leaf Rag. All other information is removed. See Sect. 9.5.

[S:98] Atonal Leaf Rag (AtonalLeafRag.mp3 1:38). The peaks are identified and removed within each beat interval in the Maple Leaf Rag, leaving an atonal rhythmic bed. See Sect. 9.5.

[S:99] Atonal Leaf Rag #2 (AtonalLeafRag2.mp3 1:53). The rhythmic bed with beat-based filters applied. See Sect. 9.5.

[S:100] Atonal Soul (AtonalSoul.mp3 2:39). The peaks are identified and removed within each beat interval in the Maple Leaf Rag, leaving an atonal rhythmic bed that is processed with beat-based filters. See Sect. 9.5.

[S:101] Sixty-Five Hertz Gong (Gong65.mp3 0:05). Spectral mapping of the gong of [S:82](1) into a harmonic template with fundamental at 65 Hz. See Sect. 9.6.1.
[S:102] Harmonic Cymbals (HarmCymbal.mp3 0:23) and (HarmCymbal.avi 0:23). An inharmonic cymbal is spectrally mapped into a harmonic spectrum. The resulting sound is pitched and capable of supporting melodies and chords. See Sect. 9.6.1.
  1. The original sample contrasted with the spectrally mapped version
  2. A simple "chord" pattern played with the original sample, and then with the spectrally mapped version

[S:103] Maple in 65 Hz (Maple65.mp3 1:52). Spectral mapping of the Maple Leaf Rag into a harmonic template with fundamental at 65 Hz. See Sect. 9.6.1.

[S:104] Sixty-Five Maples (SixtyFiveMaples.mp3 1:57). Spectral mapping of the Maple Leaf Rag into a harmonic template with fundamental at 65 Hz. The only sound source is [S:103] which is rearranged and post-processed. See Sect. 9.6.1.

[S:105] Sixty-Five Souls (Soul65PV.mp3 2:47), (Soul65FFT.mp3 2:47) Spectral mapping of Soul into a harmonic template with fundamental at 65 Hz using the phase vocoder and using the beat-synchronous FFT. See Sects. 9.6.1 and 9.8.2.

[S:106] Sixty-Five StrangeTrees (StrangeTree65.mp3 3:35). Spectral mapping of StrangeTree into a harmonic template with fundamental at 65 Hz. See Sect. 9.6.1.

[S:107] Spectral Mappings of Harmonic Sounds to 11-tet Sounds (Tim11tet.mp3 1:20). Several different instrumental sounds alternate with their 11-tet spectrally mapped versions: See Sect. 9.6.2.
  1. Harmonic trumpet compared with 11-tet trumpet
  2. Harmonic bass compared with 11-tet bass
  3. Harmonic guitar compared with 11-tet guitar
  4. Harmonic pan flute compared with 11-tet pan flute
  5. Harmonic oboe compared with 11-tet oboe
  6. Harmonic "moog" synth compared with 11-tet "moog" synth
  7. Harmonic "phase" synth compared with 11-tet "phase" synth

[S:108] The Turquoise Dabo Girl (DaboGirl.mp3 4:16). The spectrally mapped instrumental sounds of are sequenced into an 11-tet piece. Many of the kinds of effects normally associated with (harmonic) tonal music can occur, even in such strange settings as 11-tet. See Sect. 9.6.2.

[S:109] Maple N-tet PV (Maple4tetPV.mp3 0:16), (Maple5tetPV.mp3 0:16), (Maple10tetPV.mp3 0:16), (Maple100tetPV.mp3 0:16) Spectral mapping of the Maple Leaf Rag into a N-tet destination template using the phase vocoder. See Sects. 9.6.2 and 9.8.2.

[S:110] Maple N-tet FFT (Maple4tetFFT.mp3 0:16), (Maple5tetFFT.mp3 0:16), (Maple10tetFFT.mp3 0:16), (Maple100tetFFT.mp3 0:16) Spectral mapping of the Maple Leaf Rag into a N-tet destination template using the beat-based FFT. See Sects. 9.6.2 and 9.8.2.

[S:111] Pentatonic Rag (PentatonicRag 2:34). Spectral mapping of the Maple Leaf Rag into a 5-tet destination spectrum, augmented with beat-based filters and gates. See Sect. 9.6.2.

[S:112] Maple 5-tet Video (Maple5tet.avi 0:38). The first five seconds of the spectral mapping of the Maple Leaf Rag into a 5-tet destination template.
[S:113] Pentatonic Souls (PentatonicSoulPV 2:48), (PentatonicSoulFFT 2:48) Spectral mapping of Soul into a 5-tet destination spectrum by the phase vocoder and by the beat-synchronous FFT. See Sects. 9.6.2 and 9.8.2.

[S:114] Scarlatti 5-tet (Scarlatti5tet 1:40). Spectral mapping of Scarlatti's K517 sonata into a 5-tet destination spectrum. See Sect. 9.6.2.

[S:115] Make Believe Rag (MakeBelieveRag.mp3 3:37). Spectral mappings of the Maple Leaf Rag into 3, 4, 5, and 7-tet are combined and sequenced in a beat-synchronous manner. Changes in tuning play a role analogous to chord changes in a tonal context. See Sect. 9.6.3.
[S:116] Local Anomaly (LocalAnomaly.mp3 3:27). Adaptively tuned from a reorchestrated standard MIDI file drum track, Local Anomaly first appeared in and is discussed at length in Chap. 9 of Tuning, Timbre, Spectrum, Scale.

[S:117] Local Variations (LocalVariations.mp3 2:19). A single fixed spectral band filter is applied to . See Sect. 9.7.1.
[S:118] Maple Freeze Rags (MapleFreezeRag(a).mp3 1:28), (MapleFreezeRag(b).mp3 1:28) A spectral freeze is applied to the Maple Leaf Rag, with, the left and right tracks frozen rhythmically according to the necklace diagrams of Fig. 9.12. See Sect. 9.7.2.


[S:119] Soul Freezes (SoulFreeze(a).mp3 2:37), (SoulFreeze(b).mp3 2:37) A spectral freeze is applied to Soul, with the left and right tracks frozen rhythmically. See Sect. 9.7.2.

[S:120] Frozen Souls (FrozenSouls.mp3 2:37). The Soul Freezes of are used as raw material for this elaboration. See Sect. 9.7.2.

[S:121] Three Ears (ThreeEars.mp3 4:24). As each new note sounds, its pitch (and that of all currently sounding notes) is adjusted microtonally (based on its spectrum) to maximize consonance. The adaptation causes interesting glides and microtonal pitch adjustments in a perceptually sensible fashion. Three Ears first appeared in Xentonality and is discussed in Chap. 8 of Tuning, Timbre, Spectrum, Scale.


[S:122] Mirror Go Round (MirrorGoRound.mp3 3:25). The harmonic sieve is applied to Three Ears. See Sect. 9.7.3.

[S:123] Sievetree (SieveTree.mp3 3:48). The harmonic sieve is applied to Strangetree. Compare especially to Sixty-Five StrangeTrees, which spectrally maps the same piece into a harmonic series. See Sect. 9.7.3.


[S:124] Phase Space (PhaseSpace.mp3 3:10). Used for comparison with [S:125]. See Sect. 9.7.3.

[S:125] Reflective Phase (ReflectivePhase.mp3 3:26). The harmonic sieve is applied to Phase Space. See Sect. 9.7.3.

[S:126] Instant Leaf Rag (InstantLeafRag.mp3 1:51). A pitch extraction algorithm is applied to each beat interval of the Maple Leaf Rag. The sound is spectrally mapped to a destination spectrum that has a fundamental equal to the identified pitch. See Sect. 9.7.4.

[S:127] Instant Nightmare (InstantNightmare.mp3 3:36). The periodicity transform identifies the three periodicities with greatest power in each beat interval. These periodicities define the destination spectrum (consisting of all harmonics of the three basic periods). The sound is spectrally mapped to this destination spectrum. Percussion is added and the beats of the piece are rearranged. Ligon comments "Outrageously cool; Beefheart on controlled substances!" See Sect. 9.7.4.

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